Housing sealing means for rotary engines

ABSTRACT

A means of sealing two abutting portions of an engine housing at a location where the available space for sealing means is restricted, by providing a generally annular thin plate having perforations for coolant flow and having an elastomeric gasket applied to each of the inner and outer peripheral edges of the plate, which is positioned in a congruent recess in one of the two abutting housing portions.

United States Patent [15] 3,695,790 Jones [4 Oct. 3, 1972 FOR 3,196,8497/1965 Paschke ..123/8.45

ROTARY ENGINES [72] Inventor: Charles Jones, 208 Forest Drive, Exa'mnerwiuiam Freeh Hillsdale, NJ. 07642 Filed: May 24, 1971 Appl. No.: 146,051

US. Cl ..418/83, 418/ 149 Int. Cl. ..F0lc 21/06, FOlc 19/00 Field ofSearch ..418/83, 149, 142; 277/198,

[56] References Cited UNITED STATES PATENTS 3,575,538 4/1971 Berkowitz..418/83 Assistant Examiner-Leonard Smith Att0meyRaymond P. Wallace andVictor D. Behn ABSTRACT A means of sealing two abutting portions of anengine housing at a location where the available space for sealing meansis restricted, by providing a generally annular thin plate havingperforations for coolant flow and having an elastomeric gasket appliedto each of the inner and outer peripheral edges of the plate, which ispositioned in a congruent recess in one of the two abutting housingportions.

5 Claims, 7 Drawing Figures minnows 2 3,695,790 SHEET 1 OF 2 I W PRIORam" I INVENTOR. i 3a BY 6770/ /25 Jones mmmnma m2 3,695, 790

INVENTOR. Jones AGENT BY :u E R PWJML BACKGROUND OF THE INVENTION Thisinvention relates to rotary internal combustion engines, and moreparticularly to such engines havinga peripheral housing closed by a pairof end walls, the peripheral housing and end walls havingintercommunicating cavities comprising a jacket for the flow of liquidcoolant.

In rotary engines of the trochoidal type the peripheral housing is thehardest portion to cool adequately because it is of limited axial extentand therefore has only a small inner surface for heat rejection from thecombustion zone. For liquid-cooled engines the peripheral housing is adouble-walled structure, the inner and outer walls being spaced apartby'rib members defining passages therebetween for the flow of thecoolant. The end walls are hollow structures having coolant passageswith apertures around the periphery of each end wall communicating withthe passages through the peripheral housing. The coolant path isnormally through the passages of one end wall, through the passages ofthe peripheral housing, and then into the other end wall. The flow pathmay change direction in the end walls and pass back and forth severaltimes through alternating groups of passages in the peripheral housing.

In any case, the parallel end walls are assembled against the edges ofthe peripheral housing in tight relationship with the coolant aperturesof the end walls aligned with those of the peripheral housing. For thepurpose of preventing leakage of the coolant into the operating chambersof the engine or to the environment, it is necessary that sealing meansbe provided around the endfaces of the peripheral housing on both sidesof the coolant passages, that is both radially inward and radiallyoutward of the passages. It has been the prior art practice that theinner and outer wall portions of the peripheral housing should be thickenough to have a groove cut into the end edge thereof, withanelastomeric gasket positioned therein and compressed by the adjacentface of the end wall.

It is particularly undesirable to have the inner wall portion of theperipheral housing thick enough to hold such a gasket groove, since athick wall would impair the efficacy of the coolant. It has, therefore,been the practice to reduce the inner wall thickness in the zone betweena pair of thicker end portions left for the groove, but this is alsounsatisfactory because such an expedient makes die-casting or permanentmold casting of the peripheral housing impossible, and has resulted in aslow and expensive coring procedure to produce the castings.

In U. S. Pat. No. 3,575,538, that particular aspect of the problem wassolved by making only a portion of a groove in the circumferential edgeof the inner wall as a locator for an O-ring gasket, and then holdingthe gasket to that position by a metal ring. The metal ring is sodesigned and dimensioned that coolant can flow around it, so that itdoes not constitute a thickening of the wall at that location, but itdoes nevertheless partially occlude the flow through the coolantpassages. An additional difficulty is found at assembly, when a verythin O-ring of considerable length must be fitted into such a looselyformed site and remain in place while the side wall is bolted intoposition to compress the gasket.

SUMMARY The present invention overcomes the limitations of the priorart, requiring neither a thick wall nor a cumbersome coring procedure,nor yet the difficulty of handling and assembling long unsupportedO-rings. The invention provides sealing at both the inner and outer wallportions of the peripheral housing by means of a thin annular plate,having holes therethrough congruent with the flow passages, and havingan O-ring gasket attached to each of itsinner and outer circumferentialedges, whereby the gasket assembly can be handled as a'unit and hassufficient stifi'ness to locate it merely be setting it in place. Theedges of the inner and outer wall portions of the housing .aregiven acut at the corners adjacent to the coolant passages, of sufficient depth.to contain the thickness of the metal portion of the gasket assembly.The assembly is disposed in the channel thus formed and the end wallsbolted in place, compressing the O-rings which have a diameter in therelaxed condition substantially greater than the thickness of theannular plate.

It is, therefore, an object of this invention to provide housing sealingmeans for rotary engines.

It is another object to provide a rotary engine housing which can becast in a permanent mold or a die.

A further object is to provide housing sealing means wherein a gasketassembly can be readily handled as a unit and rapidly installed.

Other objects and advantages will be understood on reading the followingspecification with reference to the annexeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a semischematic verticalcross-section on the axial plane of a rotary engine of the prior art;

FIG. 2 is a fragmentary view taken on line 2-2 of FIG. .6, similar to aportion of FIG. 1, showing the invention in operative installation;

FIG. 3 is an enlarged view of the portion of FIG. 2 enclosed withincircle A;

FIG. 4 is a section of the sealing means, taken on line 4-4 of FIG. 5;

FIG. 5 is a fragmentary side view .of the sealing means;

FIG. 6 is a partial view taken on line 6-6 of FIG. 2; and

FIG. 7 is a view similar to FIG. 4' of another embodiment of the gasketassembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS ing a sealing member 19 at eachof its apexes which sweeps the epitrochoidal surface in sealingrelationship. In the liquid-cooled engine shown, each of the end walls14 is provided with internal passages 21 for the flow of coolant. Theperipheral housing 12 is of doublewalled construction, having an innerwall portion 22 and an outer wall portion 23 spaced apart therefrom byribs 24 which define coolant passages 26 (better shown in FIG. 6)through the peripheral housing in a direction generally parallel to theaxial dimension of the engine.

An inlet and outlet (not shown) are provided in the end walls, and wateror other liquid coolant flows through the passages 21 in one end wall,through passages 26 of the peripheral housing as shown by the arrows,and into the passages 21 of the other end wall, from which it isdischarged. The flow path of the coolant may be directed in apredetermined pattern by the positioning of the various passages.

The inner wall portion 22 and the outer wall portion 23 of theperipheral housing as shown in FIG. 1 have circumferential grooves cutinto their end faces, in which grooves are respectively positioned()-rings 27 and 28 or other suitable gaskets. When the engine is assembled with the end walls against the end faces of the peripheralhousing the gaskets are compressed in their grooves and prevent leakageof the coolant, either to the interior of the engine or to theenvironment.

It will be apparent that the inner wall 22 which is exposed tocombustion is an area from which heat must be rapidly removed and whichmust therefore be effectively cooled. For this reason the inner wall hasin prior art engines been made thinner in its center portion 29 betweenthe end portions which have to be thick enough to provide a gasketgroove, the inner wall therefore tapering down toward the center portionfrom the heavy end portions. To make this center portion thinnerrequires a difficult and expensive coring procedure in casting theperipheral housing, and at best still leaves a considerable thickness ofmetal at the end faces, since the slope of the tapers must be fairlylong for structural reasons and good casting procedure.

The present invention overcomes this limitation of the prior art bymaking both the inner and outer walls of the peripheral housing thinthroughout, with an improved means of positioning and retaining thegaskets. Although it is of less importance to make the outer wallportion thin as far as cooling action is concerned, nevertheless thethick outer wall of the prior art, which had a gasket groove, used moremetal and had more machining than in the present invention, which istherefore less expensive to manufacture.

. This invention also results in cost saving at assembly, since theprior art engine required handling and positioning of very flimsy, longO-rings, with the added difficulty of retaining them in their groovesuntil the side walls could be bolted on. The present device provides agasket assembly comprising a generally annular plate having elastomericdouble gaskets attached to the edges thereof, which is rigid enough tobe handled readily as a unit and which can be simply laid in placebefore bolting on the side wall.

FIG. 2 is an enlarged section similar to the bottom portion of FIG. 1,showing the gasket assembly 31 in place. The inner and outer wallportions 22a and 23a of the peripheral housing are made thin throughout,that is, of less thickness than would be required to provide gasketgrooves in their end faces. At each of the end faces of the wallportions 22a and 23a a circumferential shoulder 32 (better shown in FIG.3) is cut into the wall on the side facing the coolant passages 26between ribs 24. The edges of ribs 24 extend nearly to the end face ofthe peripheral housing, but are set far enough back not to interferewith making such a cut.

The gasket assembly 31 comprises a generally annular plate member 33which is congruent with the profile of the peripheral housing. Apertures34 are punched or machined through the annular plate, separated by ribs36, the sizing and spacing of apertures 34 and ribs 36 being congruentwith coolant passages 26 of the housing and housing ribs 24,respectively. As shown in FIGS. 3 and 4, the inner and outer edges ofplate 33 are provided with a concave groove, which may be either aradius or a V-groove as may be convenient. A deformable gasket ring 37,which may be an O-ring or other suitable elastomeric material, is bondedto each of the grooved edges by means of an adhesive 38, or vulcanizedthereto or otherwise attached. This procedure results in the generallyannular gasket assembly 31 which may be handled as a unit. An arcuateportion of such a gasket assembly is shown in FIG. 5.

FIG. 6 shows a gasket assembly 31 positioned in its channel in one endof the peripheral housing, before bolting on the associated end wall 14.FIG. 3 shows a fragmentary view of the gasket in place after applyingthe end wall. The shoulder 32 has been cut just sufficiently deep in theaxial direction to take the thickness of plate 33 of the gasket assemblywith a few thousandths clearance, so that the end wall 14 does not rideon plate 33 but abuts on the end face of the peripheral housing. Gasketrings 37 have a diameter in the relaxed state substantially greater thanthe thickness of plate 33, so that rings 37 are compressed againstshoulder 32 to form a seal when end wall 14 is applied.

In FIG. 7 there is shown another embodiment 31a of the gasket assembly.In this embodiment the inner and outer peripheral edges of plate 33a arestepped on each side to produce a thin flange 39. A molded elastomericgasket 37a of generally horseshoe cross-section is snapped over theflange, with the wings 41 of the gasket lying in the steps of the flangesubstantially flush with the surface of the plate 33a. The body of thegasket 370 has a cross-sectional diameter greater than the thickness ofthe plate, and a hollow center so that it will compress against shoulder32 as in the previously described embodiment. With gasket 31a it isunnecessary to bond the elastomeric material to the metal, it being heldby friction and by its own tension, and thus it is easier to replacegaskets 37a if it should become necessary. Either plate 33 or 33a may bemachined, but preferably is conveniently and inexpensively produced bystamping.

The coolant passages 26 in the peripheral housing may be of varioussizes and spacing, according to the cooling requirements around thehousing, but since the apertures 34 and ribs 36 of either plate 33 or33a are congruent with the coolant passages there is no obstruction offlow.

What is claimed is:

1. In a rotary internal combustion engine having a pair of end wallshaving coolant passages therein, the

end walls being spaced apart by a generally annular peripheral housinghaving double circumferential walls spaced apart by ribs definingcoolant passages therethrough in communication with the coolant passagesof the end walls, the improvement comprising: a. each of the peripheralhousing walls having a circumferential shoulder at each of its edges onthe side adjacent to the coolant passages, the two shoulders of theopposed housing walls defining a generally annular channel of shallowdepth in each end of the peripheral housing; a gasket assembly disposedin each of the channels;

c. the gasket assembly comprising a generally annular plate havingapertures therethrough congruent with the coolant passages of theperipheral housing, and a continuous elastomeric gasket attached to andsurrounding each edge of the generally annular plate.

2. The combination recited in claim 1, wherein each of the generallyannular channels has an axial depth slightly greater than the thicknessof the generally annular plate so that the end walls abut the end facesof the peripheral housing, and the elastomeric gaskets have across-sectional diameter greater than the thickness of the plate, sothat they are compressed by the end walls.

3. The combination recited in claim 2, wherein the generally annularplate has a concave groove in each of its inner and outer edges, and theelastomeric gaskets are bonded to the grooved edges, so that the plateand the gaskets comprise a unitary assembly.

4. The combination recited in claim 2, wherein each of the elastomericgaskets has a generally horseshoe cross-section with a groove betweenthe ends of the horseshoe shape, the groove embracing the edge of thegenerally annular plate.

5. The combination recited in claim 4, wherein the generally annularplate has a circumferential flange extending from each of its inner andouter edges, the flange being thinner than the remainder of the plate,the groove of the gasket embracing the flange and the ends of thehorseshoe section lying substantially flush with the surface of theplate on each side.

. I I UNITEIl STATES PATENT. OFFICE CERTIFICATE OF CORRECTION Patent No.3, 95,790 Dated October 3, 1972 Intentofls) Charles Jones It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

7 On the cover sheet following item (72 insert the following:

(73) Assignee: Curtiss-Wr'ight Corporation-- Signed and sealed this 17thday of April .1973.

(SEAL) Attest:

r EDWARD M.FLETCHER,'JR.

ROBERT GOTTSCI-IALK Attesting Officer Commissioner of Patents F ORMPO-1050 (10-69) USCOMM-DC 60376-P69 1.5, GOVERNMENT PRINTING OFFICE I9690-366-334,'

1. In a rotary internal combustion engine having a pair of end wallshaving coolant passages therein, the end walls being spaced apart by agenerally annular peripheral housing having double circumferential wallsspaced apart by ribs defining coolant passages therethrough incommunication with the coolant passages of the end walls, theimprovement comprising: a. each of the peripheral housing walls having acircumferential shoulder at each of its edges on the side adjacent tothe coolant passages, the two shoulders of the opposed housing wallsdefining a generally annular channel of shallow depth in each end of theperipheral housing; b. a gasket assembly disposed in each of thechannels; c. the gasket assembly comprising a generally annular platehaving apertures therethrough congruent with the coolant passages of theperipheral housing, and a continuous elastomeric gasket attached to andsurrounding each edge of the generally annular plate.
 2. The combinationrecited in claim 1, wherein each of the generally annular channels hasan axial depth slightly greater than the thickness of the generallyannular plate so that the end walls abut the end faces of the peripheralhousing, and the elastomeric gaskets have a cross-sectional diametergreater than the thickness of the plate, so that they are compressed bythe end walls.
 3. The combination recited in claim 2, wherein thegenerally annular plate has a concave groove in each of its inner andouter edges, and the elastomeric gaskets are bonded to the groovededges, so that the plate and the gaskets comprise a unitary assembly. 4.The combination recited in claim 2, wherein each of the elastomericgaskets has a generally horseshoe cross-section with a groove betweenthe ends of the horseshoe shape, the groove embracing the edge of thegenerally annular plate.
 5. The combination recited in claim 4, whereinthe generally annular plate has a circumferential flange extending fromeach of its inner and outer edges, the flange being thinner than theremainder of the plate, the groove of the gasket embracing the flangeand the ends of the horseshoe section lying substantially flush with thesurface of the plate on each sidE.